From DE 195 45 437 A1 by the present applicant an oil pump designed as a radial piston pump is known, which is arranged on a guide-wheel spindle of an automatic transmission fixed on the housing and is driven by the pump gear of a converter. The pump is positioned between the converter and the transmission part of the automatic transmission and is driven via the pump gear at the speed of the engine. The radial piston pump comprises an eccentric which is driven by drive fingers fixed on the pump gear. Inside the guide-wheel spindle fixed on the housing is arranged a driveshaft (not shown) of the transmission, which is driven by the turbine wheel of the converter. Thus, the radial piston pump is arranged coaxially with a transmission shaft but is not attached to it. Particularly because of the design as a radial piston pump, the structural depth in the radial direction is large. This pump drive is called a converter neck pump, and by virtue of the converter neck the drive can also be used for pumps with other designs, such as internal-gear-type pumps. Since the eccentric is coupled to the engine, the pump operates so long as the engine is running, i.e. it does not deliver anything when the engine is stopped but the vehicle is still moving. This coaxial arrangement is also called the in-line configuration.
Also known are so-termed off-axis configurations as described in DE 10 2006 043 047 A1 by the present applicant and in DE 10 2008 005 239 A1. An internal gear pump designed as a half-moon pump is fixed on a transmission housing wall of a dual-clutch transmission and arranged next to the dual clutch. The oil pump is driven by the clutch housing via a gear stage on a pump shaft. Thus, the axis of the pump shaft or of the pump gear (of the internal rotor) is positioned parallel and offset relative to the axis of the dual clutch and the two driveshafts. This off-axis design takes up a relatively large structural space in both the radial and axial directions, which is not always available in every transmission. The oil pump is always driven at engine speed via the clutch hub, a hub bell and a hub sleeve. When the engine is at rest and the vehicle is rolling, the pump delivers no oil. FIG. 1 of DE 10 2008 005 239 A1 shows the whole of the dual-clutch transmission with several transmission shafts: a hollow shaft can be driven by a first clutch and a coaxially arranged solid shaft can be driven by a second clutch; thus, the hollow and solid shafts are driveshafts. Moreover, the dual-clutch transmission comprises a countershaft and a pinion shaft, which drives an output shaft. The oil pump is arranged outside the transmission, i.e. inside a fixed housing of the dual clutch.